Regression line of typing speed on weekly practice time, the correlation coefficient and an interpolated prediction
Regression line of typing speed on weekly practice time, the correlation coefficient and an interpolated prediction
5 marks
Eight members of a typing club recorded the number of hours, \(h\), that they practise each week and their typing speed, \(W\) words per minute. The results are shown below.
| Practice (\(h\) hours per week) | \(2\) | \(5\) | \(3\) | \(8\) | \(6\) | \(4\) | \(7\) | \(1\) |
|---|---|---|---|---|---|---|---|---|
| Typing speed (\(W\) words per minute) | \(33\) | \(44\) | \(37\) | \(57\) | \(48\) | \(41\) | \(55\) | \(26\) |
The regression line of \(W\) on \(h\) has equation \(W=ah+b\).
- Find \(a\) and \(b\).[2]
- Write down the value of Pearson's product-moment correlation coefficient, \(r\), for these data.[1]
- A member of the club practises for \(4.5\) hours each week. Use your regression line to estimate this member's typing speed.[2]
Solution:
Solution locked
680+ questions here come with free worked solutions. A free account saves your questions and progress; this one needs tuition enrolment.
Create a free account to practise similar questions.
Answer:(a) \(a=4.32,\ b=23.2\) (b) \(r=0.994\) (c) \(42.6\) words per minute
Need help? Join our JC Math tuition classes.
Learn more